From: kernel test robot <oliver.sang@intel.com>
To: Ujwal Kundur <ujwal.kundur@gmail.com>
Cc: <oe-lkp@lists.linux.dev>, <lkp@intel.com>,
<linux-block@vger.kernel.org>, <axboe@kernel.dk>,
<ming.lei@redhat.com>, <linux-kernel@vger.kernel.org>,
Ujwal Kundur <ujwal.kundur@gmail.com>,
<syzbot+2e9e529ac0b319316453@syzkaller.appspotmail.com>,
<oliver.sang@intel.com>
Subject: Re: [PATCH] block: prevent deadlock in del_gendisk()
Date: Fri, 8 Aug 2025 16:41:16 +0800 [thread overview]
Message-ID: <202508081000.cb134e91-lkp@intel.com> (raw)
In-Reply-To: <20250803134114.2707-1-ujwal.kundur@gmail.com>
Hello,
kernel test robot noticed "BUG:kernel_NULL_pointer_dereference,address" on:
commit: 00ff643264f9f5c300898a591fa4b83a62c43950 ("[PATCH] block: prevent deadlock in del_gendisk()")
url: https://github.com/intel-lab-lkp/linux/commits/Ujwal-Kundur/block-prevent-deadlock-in-del_gendisk/20250803-214237
base: https://git.kernel.org/cgit/linux/kernel/git/axboe/linux-block.git for-next
patch link: https://lore.kernel.org/all/20250803134114.2707-1-ujwal.kundur@gmail.com/
patch subject: [PATCH] block: prevent deadlock in del_gendisk()
in testcase: phoronix-test-suite
version:
with following parameters:
test: svt-av1-2.11.1
option_a: 2
option_b: Bosphorus 1080p
cpufreq_governor: performance
config: x86_64-rhel-9.4
compiler: gcc-12
test machine: 96 threads 2 sockets Intel(R) Xeon(R) Gold 6252 CPU @ 2.10GHz (Cascade Lake) with 512G memory
(please refer to attached dmesg/kmsg for entire log/backtrace)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <oliver.sang@intel.com>
| Closes: https://lore.kernel.org/oe-lkp/202508081000.cb134e91-lkp@intel.com
[ 24.331036][ T1884] BUG: kernel NULL pointer dereference, address: 00000000000000a8
[ 24.339231][ T1884] #PF: supervisor write access in kernel mode
[ 24.345493][ T1884] #PF: error_code(0x0002) - not-present page
[ 24.351631][ T1884] PGD 0 P4D 0
[ 24.355133][ T1884] Oops: Oops: 0002 [#1] SMP NOPTI
[ 24.360264][ T1884] CPU: 26 UID: 0 PID: 1884 Comm: dockerd Tainted: G S 6.16.0-04436-g00ff643264f9 #1 VOLUNTARY
[ 24.372434][ T1884] Tainted: [S]=CPU_OUT_OF_SPEC
[ 24.377290][ T1884] Hardware name: Intel Corporation S2600WFT/S2600WFT, BIOS SE5C620.86B.02.01.0008.031920191559 03/19/2019
[ 24.388664][ T1884] RIP: 0010:down_read (arch/x86/include/asm/atomic64_64.h:79 include/linux/atomic/atomic-arch-fallback.h:2723 include/linux/atomic/atomic-long.h:163 include/linux/atomic/atomic-instrumented.h:3298 kernel/locking/rwsem.c:250 kernel/locking/rwsem.c:1245 kernel/locking/rwsem.c:1259 kernel/locking/rwsem.c:1524)
[ 24.393632][ T1884] Code: 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 0f 1f 44 00 00 53 48 89 fb e8 ae c0 ff ff be 00 01 00 00 <f0> 48 0f c1 33 48 81 c6 00 01 00 00 78 3f 48 b8 07 00 00 00 00 00
All code
========
0: 00 00 add %al,(%rax)
2: 00 90 90 90 90 90 add %dl,-0x6f6f6f70(%rax)
8: 90 nop
9: 90 nop
a: 90 nop
b: 90 nop
c: 90 nop
d: 90 nop
e: 90 nop
f: 90 nop
10: 90 nop
11: 90 nop
12: 90 nop
13: f3 0f 1e fa endbr64
17: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1)
1c: 53 push %rbx
1d: 48 89 fb mov %rdi,%rbx
20: e8 ae c0 ff ff call 0xffffffffffffc0d3
25: be 00 01 00 00 mov $0x100,%esi
2a:* f0 48 0f c1 33 lock xadd %rsi,(%rbx) <-- trapping instruction
2f: 48 81 c6 00 01 00 00 add $0x100,%rsi
36: 78 3f js 0x77
38: 48 rex.W
39: b8 07 00 00 00 mov $0x7,%eax
...
Code starting with the faulting instruction
===========================================
0: f0 48 0f c1 33 lock xadd %rsi,(%rbx)
5: 48 81 c6 00 01 00 00 add $0x100,%rsi
c: 78 3f js 0x4d
e: 48 rex.W
f: b8 07 00 00 00 mov $0x7,%eax
...
[ 24.413635][ T1884] RSP: 0018:ffffc900211f3918 EFLAGS: 00010246
[ 24.419821][ T1884] RAX: 0000000000000000 RBX: 00000000000000a8 RCX: 00000000000001f0
[ 24.427912][ T1884] RDX: 00000000000001ef RSI: 0000000000000100 RDI: 00000000000000a8
[ 24.436003][ T1884] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
[ 24.444092][ T1884] R10: 0000000000000000 R11: 0000000000000000 R12: 00000000000000a8
[ 24.452181][ T1884] R13: ffff88c1841e87a0 R14: ffff88c08b28ad68 R15: ffff88c0ce5b2200
[ 24.460273][ T1884] FS: 00007ff8a3fff6c0(0000) GS:ffff88f027468000(0000) knlGS:0000000000000000
[ 24.469318][ T1884] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 24.476016][ T1884] CR2: 00000000000000a8 CR3: 000000010e760004 CR4: 00000000007726f0
[ 24.484104][ T1884] PKRU: 55555554
[ 24.487751][ T1884] Call Trace:
[ 24.491131][ T1884] <TASK>
[ 24.494147][ T1884] __del_gendisk (block/genhd.c:745)
[ 24.498810][ T1884] cleanup_mapped_device (drivers/md/dm.c:2243) dm_mod
[ 24.504959][ T1884] __dm_destroy (include/linux/list.h:373 drivers/md/dm.c:2397 drivers/md/dm.c:2730) dm_mod
[ 24.510321][ T1884] ? __pfx_dev_remove (drivers/md/dm-ioctl.c:978) dm_mod
[ 24.516029][ T1884] dev_remove (drivers/md/dm-ioctl.c:1029) dm_mod
[ 24.521215][ T1884] ctl_ioctl (drivers/md/dm-ioctl.c:2101) dm_mod
[ 24.526310][ T1884] dm_ctl_ioctl (drivers/md/dm-ioctl.c:2123) dm_mod
[ 24.531399][ T1884] __x64_sys_ioctl (fs/ioctl.c:51 fs/ioctl.c:598 fs/ioctl.c:584 fs/ioctl.c:584)
[ 24.536040][ T1884] ? change_protection_range (mm/mprotect.c:498 mm/mprotect.c:526)
[ 24.541726][ T1884] do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94)
[ 24.546279][ T1884] ? get_page_from_freelist (mm/page_alloc.c:1083 mm/page_alloc.c:1702 mm/page_alloc.c:1712 mm/page_alloc.c:3669)
[ 24.551869][ T1884] ? __alloc_frozen_pages_noprof (mm/page_alloc.c:4959)
[ 24.557894][ T1884] ? mod_memcg_lruvec_state (mm/memcontrol.c:576 mm/memcontrol.c:564 mm/memcontrol.c:754)
[ 24.563495][ T1884] ? __lruvec_stat_mod_folio (mm/memcontrol.c:800)
[ 24.569006][ T1884] ? __folio_mod_stat (mm/rmap.c:1414)
[ 24.573905][ T1884] ? folio_add_new_anon_rmap (arch/x86/include/asm/bitops.h:206 arch/x86/include/asm/bitops.h:238 include/asm-generic/bitops/instrumented-non-atomic.h:142 include/linux/page-flags.h:867 include/linux/page-flags.h:888 include/linux/mm.h:992 mm/rmap.c:1609)
[ 24.579493][ T1884] ? do_anonymous_page (mm/memory.c:5153)
[ 24.584646][ T1884] ? __handle_mm_fault (mm/memory.c:6230)
[ 24.589805][ T1884] ? do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94)
[ 24.594520][ T1884] ? count_memcg_events (mm/memcontrol.c:576 mm/memcontrol.c:564 mm/memcontrol.c:848)
[ 24.599749][ T1884] ? handle_mm_fault (include/linux/memcontrol.h:978 include/linux/memcontrol.h:985 mm/memory.c:6264 mm/memory.c:6425)
[ 24.604635][ T1884] ? do_user_addr_fault (arch/x86/mm/fault.c:1337)
[ 24.609863][ T1884] ? clear_bhb_loop (arch/x86/entry/entry_64.S:1548)
[ 24.614572][ T1884] ? clear_bhb_loop (arch/x86/entry/entry_64.S:1548)
[ 24.619279][ T1884] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[ 24.625200][ T1884] RIP: 0033:0x7ff9476c3d1b
[ 24.629648][ T1884] Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1c 48 8b 44 24 18 64 48 2b 04 25 28 00 00
All code
========
0: 00 48 89 add %cl,-0x77(%rax)
3: 44 24 18 rex.R and $0x18,%al
6: 31 c0 xor %eax,%eax
8: 48 8d 44 24 60 lea 0x60(%rsp),%rax
d: c7 04 24 10 00 00 00 movl $0x10,(%rsp)
14: 48 89 44 24 08 mov %rax,0x8(%rsp)
19: 48 8d 44 24 20 lea 0x20(%rsp),%rax
1e: 48 89 44 24 10 mov %rax,0x10(%rsp)
23: b8 10 00 00 00 mov $0x10,%eax
28: 0f 05 syscall
2a:* 89 c2 mov %eax,%edx <-- trapping instruction
2c: 3d 00 f0 ff ff cmp $0xfffff000,%eax
31: 77 1c ja 0x4f
33: 48 8b 44 24 18 mov 0x18(%rsp),%rax
38: 64 fs
39: 48 rex.W
3a: 2b .byte 0x2b
3b: 04 25 add $0x25,%al
3d: 28 00 sub %al,(%rax)
...
Code starting with the faulting instruction
===========================================
0: 89 c2 mov %eax,%edx
2: 3d 00 f0 ff ff cmp $0xfffff000,%eax
7: 77 1c ja 0x25
9: 48 8b 44 24 18 mov 0x18(%rsp),%rax
e: 64 fs
f: 48 rex.W
10: 2b .byte 0x2b
11: 04 25 add $0x25,%al
13: 28 00 sub %al,(%rax)
The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20250808/202508081000.cb134e91-lkp@intel.com
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
prev parent reply other threads:[~2025-08-08 8:41 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-03 13:41 [PATCH] block: prevent deadlock in del_gendisk() Ujwal Kundur
2025-08-04 7:51 ` Yu Kuai
2025-08-05 11:59 ` Hillf Danton
2025-08-06 0:58 ` Yu Kuai
2025-08-06 15:17 ` Ujwal Kundur
2025-08-08 8:41 ` kernel test robot [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=202508081000.cb134e91-lkp@intel.com \
--to=oliver.sang@intel.com \
--cc=axboe@kernel.dk \
--cc=linux-block@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=lkp@intel.com \
--cc=ming.lei@redhat.com \
--cc=oe-lkp@lists.linux.dev \
--cc=syzbot+2e9e529ac0b319316453@syzkaller.appspotmail.com \
--cc=ujwal.kundur@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.